b 1. Field of the Invention
This invention relates to solenoids typically used to control the flow of a fluid.
2. Description of Related Art
Solenoids are used in a variety of applications, such as flow control valves in a hydraulic or pneumatic system. Typically solenoid valves are placed between a pump or compressor and an actuator, such that the valve will allow fluid to flow to the actuator when the solenoid is energized. The flow of fluid causes the actuator to extend, retract or rotate, depending upon the construction of the actuating device. The actuator can be part of a robot or other automated equipment, wherein movement of the actuator performs some type of work function such as lifting, drilling, etc.
Automated machines commonly have a plurality of actuators and solenoids all connected to an electronic controller, which energizes the solenoids in accordance with a program stored within the controller. In some applications the movement of the actuator is dependent upon the amount of time that the solenoid is energized. Typically, there is a lag between the time that the solenoid is energized and the moment when the valve is opened. To have an accurate movement of the actuator, this lag time must be compensated for by the programmer. The lag time is amplified by any inefficient use of the magnetic flux generated by the coil. It would therefore be desirable to have an efficient solenoid that has a short time difference between the energizing of the solenoid coil and the complete movement of the solenoid armature.
In general, all valves have a number of moving parts that are subject to wear and must be replaced, thereby reducing the life of the device. When the valve is part of a machine, the equipment must be shut down while the valve is replaced or repaired. As the frequency of valve switching increases, the life of the part becomes shorter. It would therefore be desirable to have a high speed solenoid valve which has a long operating life.